In systems in which electrical current is transmitted through circuits, such as electric and hybrid electric vehicles, for example, provision is often made to protect service personnel and the like from high voltages which may be used in such systems. High-voltage power systems may utilize energy storage devices which require a certain amount of time to discharge electrical power prior to access of a component in the system. Physical barriers such as protective covers and lock-out devices, for example, may be used to prevent premature physical contact of service or other personnel with the components in a high-voltage power system.
A high-voltage interlock (HVIL) system utilizes an HV interlock control device to open an electrical circuit and prevent flow of high voltage (HV) current through the system before access to a component in the system is permitted. Current implementation of high voltage interlocks utilizes a hard wired circuit that runs through interlock switches at all access points for the HV components and connectors in the system. The high voltage current can be present in the system until any of the HV components is individually accessed such as by the removal of an access cover or connector, for example, which opens the interlock switch for the HV component and breaks the circuit of the HV interlock system.
In implementation of the current HVIL system, the HV circuit is hard-wired through an interlock switch at the access point for each HV component in the system. Direct access of each HV component results in termination and discharge of electrical current through all HV components in the system. This arrangement, however, increases the complexity and cost of the system. Therefore, a centralized HVIL system which is characterized by simplicity in design is needed.